Condensed Consolidated Statements of Cash Flows (USD $) In Millions	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010
Cash flows from operating activities:
Net income	$ 142.3	$ 218.8
Adjustments to reconcile Net income to Net cash provided by operating activities:
Depreciation and amortization	106.0	105.3
Deferred income taxes	70.5	38.7
Unamortized investment tax credit	(2.1)	(2.1)
Charge for early redemption of debt	15.3
Changes in certain assets and liabilities:
Accounts receivable	21.1	7.9
Inventories	(11.5)	10.6
Prepaid taxes	(27.0)	(0.9)
Taxes applicable to subsequent years	47.7	44.2
Deferred regulatory costs, net	7.9	7.0
Accounts payable	(13.4)	(4.7)
Accrued taxes payable	(58.2)	(58.1)
Accrued interest payable	(3.1)	(5.6)
Pension, retiree and other benefits	(31.7)	(54.6)
Insurance and claims costs	4.1	(0.3)
Other	(3.1)	25.4
Net cash provided by operating activities	264.8	331.6
Cash flows from investing activities:
Capital expenditures	(141.3)	(113.7)
Purchase of MC Squared	(8.3)
Purchases of short-term investments and securities	(1.7)	(62.7)
Sales of short-term investments and securities	70.9	14.4
Other	1.5	1.7
Net cash used for investing activities	(78.9)	(160.3)
Cash flows from financing activities:
Dividends paid on common stock	(113.8)	(104.8)
Early redemption of Capital Trust II debt	(122.0)
Premium paid for early redemption of debt	(12.2)
Payment of MC Squared debt	(13.5)
Payment of long-term debt	(297.4)	0
Issuance of long-term debt	300.0	0
Withdrawals from revolving credit facilities	50.0
Repayments of borrowings from revolving credit facilities	(50.0)
Repurchase of DPL common stock		(3.9)
Exercise of stock options	1.6	1.4
Exercise of warrants	14.7	0
Tax impact related to exercise of stock options	0.3	0.2
Net cash used for financing activities	(242.3)	(107.1)
Cash and cash equivalents:
Net change	(56.4)	64.2
Balance at beginning of period	124.0	74.9
Cash and cash equivalents at end of period	67.6	139.1
Supplemental cash flow information:
Interest paid, net of amounts capitalized	49.4	59.6
Income taxes paid, net	25.5	60.8
Non-cash financing and investing activities:
Accruals for capital expenditures	14.8	14.1
Long-term liability incurred for purchase of assets	18.7
THE DAYTON POWER AND LIGHT COMPANY [Member]
Cash flows from operating activities:
Net income	147.4	214.7
Adjustments to reconcile Net income to Net cash provided by operating activities:
Depreciation and amortization	100.3	98.4
Deferred income taxes	56.1	36.9
Unamortized investment tax credit	(2.1)	(2.1)
Changes in certain assets and liabilities:
Accounts receivable	26.4	27.5
Inventories	(11.5)	10.3
Prepaid taxes	(11.5)	(0.9)
Taxes applicable to subsequent years	47.1	44.0
Deferred regulatory costs, net	7.9	7.0
Accounts payable	(14.9)	(6.1)
Accrued taxes payable	(58.5)	(55.6)
Accrued interest payable	7.4	2.2
Pension, retiree and other benefits	(31.7)	(54.6)
Other	24.4	16.3
Net cash provided by operating activities	286.8	338.0
Cash flows from investing activities:
Capital expenditures	(139.9)	(112.3)
Other	1.4	1.7
Net cash used for investing activities	(138.5)	(110.6)
Cash flows from financing activities:
Dividends paid on common stock	(180.0)	(150.0)
Dividends paid on preferred stock	(0.6)	(0.6)
Withdrawals from revolving credit facilities	50.0
Repayments of borrowings from revolving credit facilities	(50.0)
Net cash used for financing activities	(180.6)	(150.6)
Cash and cash equivalents:
Net change	(32.3)	76.8
Balance at beginning of period	54.0	57.1
Cash and cash equivalents at end of period	21.7	133.9
Supplemental cash flow information:
Interest paid, net of amounts capitalized	22.2	27.6
Income taxes paid, net	24.6	60.7
Non-cash financing and investing activities:
Accruals for capital expenditures	14.8	14.1
Long-term liability incurred for purchase of assets	$ 18.7